Maybe what people were thinking of was this:
Green Car Congress: TIGERS: Exhaust Gas to Electricity for Reductions in Fuel Consumption
Shouldn't be any need to mess with complicated mechanical linkages, just use electronics to control the alternator field current, and thus the amount of generation. At idle, no current, thus no load other than a bit of bearing friction.
Would be neat if it could be made dual-purpose, to function as alternator and turbocharger. Instead of a waste gate, you'd control boost by varying alternator load... So where's the aftermarket kit for my Insight?